[AMP OP&Test] Update unittest of fp16 for slice op (#51036)

* update unittest of fp16 for slice op

* set atol to default value

* update max_relative_eror

python/paddle/fluid/tests/unittests/test_slice_op.py

@@ -488,7 +488,7 @@ class TestFP16(OpTest):
     def test_check_output(self):
         place = core.CUDAPlace(0)
         if core.is_float16_supported(place):
-            self.check_output_with_place(place, atol=1e-5, check_prim=True)
+            self.check_output_with_place(place, check_prim=True)
 
     def test_check_grad_normal(self):
         place = core.CUDAPlace(0)
@@ -498,7 +498,6 @@ class TestFP16(OpTest):
                 place,
                 ['Input'],
                 'Out',
-                max_relative_error=0.006,
                 check_prim=True,
             )
 
@@ -533,7 +532,7 @@ class TestFP16_2(OpTest):
     def test_check_output(self):
         place = core.CUDAPlace(0)
         if core.is_float16_supported(place):
-            self.check_output_with_place(place, atol=1e-5, check_prim=True)
+            self.check_output_with_place(place, check_prim=True)
 
     def test_check_grad_normal(self):
         place = core.CUDAPlace(0)
@@ -542,7 +541,6 @@ class TestFP16_2(OpTest):
                 place,
                 ['Input'],
                 'Out',
-                max_relative_error=0.006,
                 numeric_grad_delta=0.5,
                 check_prim=True,
             )